Commercial production of integrated circuit devices, such as memory dice, may involve fabrication of a large number of identical circuit patterns on a single semiconductor wafer or other bulk semiconductor substrate. It is a continuing goal of semiconductor manufacturers to increase the density of semiconductor devices fabricated on a given size of semiconductor substrate to achieve increased yield of semiconductor devices and enhanced performance thereof.
One method for increasing the density of semiconductor devices in a semiconductor assembly is to create vias (i.e., through-holes) that extend entirely through a semiconductor die; and specifically that extend from an active surface of the die to the opposing backside surface of the die. The vias are filled with an electrically conductive material to form through-substrate interconnects that provide electrical pathways from the active surface of the die to the backside surface of the die. The through-substrate interconnects may be electrically coupled to electrical contacts that are along the backside of the die, and that extend to circuit components external of the die. In some applications, the die may be incorporated into a three-dimensional multichip module (3-D MCM), and the circuit components external of the die may be comprised by another semiconductor die and/or by a carrier substrate.
Various methods for forming vias in semiconductor substrates have been disclosed. For instance, U.S. Pat. Nos. 7,855,140, 7,626,269 and 6,943,106 describe example methods that may be utilized to form through-substrate interconnects.
Thermally-induced problems may occur with conventionally-formed through-substrate interconnects. Such problems may result from stresses occurring as a result of the different rates of thermal expansion of the conductive materials within the interconnects (for instance, copper) relative to other materials of a semiconductor die. It would be desirable to develop new through-substrate interconnect architectures which alleviate or prevent such thermally-induced problems, and to develop methods for fabricating such architectures.